Single mode optical fiber

摘要

A single mode optical fiber comprises from the center to the periphery a core, at least first and second depressed claddings, and an outer cladding. The core has a radius (Rco) comprised between 3.5 pm and 5.5 pm and an index difference with the outer cladding (Dnco-Dnout) comprised between 0 and 3.10 3; the first depressed cladding has a radius (Rcll) comprised between 9 pm and 15 pm and an index difference with the outer cladding (Dncll-Dnout) comprised between 5.5.10-3 and -2.5.10-3; the second depressed cladding has a radius (Rcl2) comprised between 38 pm and 42 pm and an index difference with the first depressed cladding (Dncl2-Dncll) comprised between -0.5.10-3 and 0.5.10-3; and the outer cladding has a radius comprised between 61.5 pm and 63.5 pm. A fiber with reduced attenuation can be manufactured at reduced cost. Figure 1 iDnlco Dnom Dnen tube Rcii Figure 2 DncoDnu Dueli RI* Re12